For both safety and security reasons, automotive manufacturers in recent years have included "key-in-ignition" warning devices in most vehicle models. These devices, which employ either an audible or visual warning, or both, typically are independent of the electrical ignition switch, a component of the ignition switch mechanism.
Typically, the ignition switch mechanism comprises a mechanical key cylinder, an electrical ignition switch, an electrical "key-in-ignition" warning switch, and mechanical linkages connecting these devices. The key cylinder allows the user to operate the ignition switch when the correct key is inserted. The ignition switch is then operated via the linkage when the key cylinder is rotated. Completely inserting the key into the ignition enables the warning device(s) in the "key-in-ignition" circuit and subsequently activates the warning if the driver's door opens prior to the key being removed.
Prior art methods of actuating the "key-in-ignition" warning switch have included mechanical devices operating in conjunction with they key cylinder of the ignition assembly. The mechanical device, for example a rod and clip assembly, would typically extend through the steering column of the auto and actuate the "key-in-ignition" switch independent of the ignition switch.
One of the disadvantages of this type of system is the necessity of separate switches for both the ignition and the "key-in-ignition" warning system. Two switches translates into additional assembly time to mount the switches, twice the mounting hardware, and an increase in cost associated with using two switches.